Piston and piston expanding ring



May 29, 1934. I "w CQQMBS AL 1,960,989

' PISTON AND PISTON EXPANDING RING Filed Oct. 19. 1952 J i 10 Lesiz'efifooms Cfi Arthur mvENT Rs THEIR ATTORNEYS Patented May 29, 1934 PATENT! OFFICE 1,960,989 PISTON AND PISTON EXPANDING RING Leslie W. Ooombs and Arthur W. Kushinsky, Chicago, Ill.

Application October 19, 1932, Serial No. 638,615 8 Claims. (Cl. 309-12) This invention relates to certain novel improvements in pistons and piston-expanding rings, and has for its principal object the provision of an improved construction of this character which will be highly efficient in use and economical in manufacture and installation.

Objects of this invention are: to provide new and generally improved pistons and piston-expanding rings; to provide new and improved expander ring and piston skirt constructions for preventing undesired movement of the expander ring axially and circumferentially relative to the piston skirt; and to provide a new and improved piston skirt and expander ring construction in which the expander ring may be installed with the expenditure of a minimum amount of time and labor by the use of a simple hand drill and without the need for or use of a vise and reaming tool, such as are required to install the prior art expander rings.

Other objects will appear hereinafter. The invention consists in the novel combination and arrangement of parts to be hereinafter described and claimed. 7

The invention will be best understood by reference to the accompanying drawing, showing the preferred form of construction, and in which: Fig. 1 is a side elevational view of a preferred form of the invention, a section thereof being broken away to show the construction thereof; Fig. 2 is a sectional view on line 2-2 in Fig. 1; Fig. 3 is a sectional view on line 3-3 in Fig. 2; Fig. 4 is a perspective view of the new expanding ring embodied in the form or the invention shown in Figs. 1, 2 and 3;

Fig. 5 is a side elevational view of a modified form of the invention with a part of the piston broken away to reveal the construction thereof;

Fig. 6 is a sectional view on the line 6-6 in Fig. 5; and

Fig. 7 is a perspective view of a modified form of construction of the invention.

In the preferred form of the invention, illustrated in Figs. 1 to 4, inclusive, of the drawing, 5 an aluminum or other expansible alloy piston is indicated generally at 10. The piston 10 comprises a split skirt 11 provided with a transverse slot 12 immediately below the bottom ring groove 13, and having an inclined axially or longitudinally extending slot 14 extending from the slot 12 to the bottom of the piston skirt 11. Up to this point the construction of the piston 10 is, of course, conventional, the present invention, insofar as it relates to the piston 10, having to do with the construction thereof provided for mounting the new piston skirt expanding ring, generally indicated at 15, therein. 7

The new split expanding ring 15 is substantially semi-circular in cross section and is mount- 0 ed in the skirt 11-by means of fastening elements in the form of headed studs 16, each of which has a shank portion 17 that is fixedly seated in an aperture 19 formed in the skirt 11; each of these studs 16' having a head 18 that projects into the groove 20 formed on the outer side of the ring by the semi-circular cross sectional construction thereof.

The new ring 15 has tool-receiving or hand grip portions 21 struck out therefrom inwardly to facilitate the insertion of the ring into the skirt 11 and its removal therefrom.

The ring 15 is flattened from a true circle along one diameter thereof, during installation, so as to leave the clearances 22 (Fig. 2) between the ring and the piston skirt' 11 to allow for the irregular curvatures and excess metal that are frequently found in these portions of piston skirts.

The ring 15 has upper and lower bearing edges 23 and 24, and these edges, being relatively sharp, bear against and gouge into the inner wall of the skirt 11 under the pressure incidental to the tendency of the ring to expand when installed in the piston, and thus prevent the ring 15 from rocking up and down, that is, from moving axially of and relative to the skirt 11.

Slots 25 are provided in the ring 15 by the struck-out portions 21 and the heads 18 of two of the studs 16 project into these slots (Fig. 2). Rotation of the ring 15 relative to and circumferentially of the piston is prevented by the two studs 16 which project into the slots 25 (Fig. 2).

The struck-out grip portions are located near, but at points somewhat removed from, the ends of the ring 15; there being thus provided end portions 27 between the grip portions 21 and the ends of the ring. By thus constructing the grip portions 21, rather than by curling or bending the end portions of the ring, as has been done in the prior art, the bearing edges 23 and 24 of the ring 15 in use bear against the piston skirt throughout their entire lengths and thus provide the maximum bearing surface. The pressure of the expanded ring is thus uniformly distributed over a maximum area of the skirt 11.

This construction of the ring likewise makes it possible to grind off a part or substantially allof the end portions 27 of the ring when it is desired to reduce the size of the ring whenever necessary to fit a particular piston. Likewise, the bearing edges 23 and 24 may be ground out at points where undesirable projections of metal or irregularities occur in the piston skirt so as to accommodate the ring to the skirt, thus avoiding the necessity of arranging the piston in a vise and reaming out of the piston these irregularities or projections, as has frequently been found necessary to install the prior art rings.

It is likewise possible with this type of ring construction to reduce the tension of the ring and the pressure exerted thereby on the piston skirt 11. This may be done by removing the ring and grinding down the bearing edges 23 and 24 of the ring.

Furthermore, the new ring 15 eliminates the necessity for a vise and reaming tool, heretofore required to install piston skirt expander rings, since the new ring 15 may be installed by simply drilling the holes 19 in the piston skirt by means of a simple hand drill, inserting the fastening elements or pins 16 into the holes 19, and then inserting the ring in the skirt.

In the modification of the invention shown in Figs. 5 and 6, the piston, generally indicated at 28, is provided with a transverse slot 29 and an inclined axially or longitudinally extending slot 30 which extends from the slot 29 to the bottom of the piston skirt 31. This piston 2.8 has webs 32 formed therein below the wrist pin bosses 33 and it also has internal strengthening ribs 34 formed in the skirt below the web 32. Provided in the Webs 32 are diametrically opposed slots 35. The expander ring 36 rests upon the ribs 34 and has portions (Fig. 6) which project into the slots 35; thereby securing the'ring against movement longitudinally or axially of, and relative to, the piston 28. The ring 36 has end portions 3'7 which are angled back upon the ring itself. These end portions 37 provide hand or tool grips and are offset upwardly out of the plane in which the body of the ring lies so that in use they bear against the inside walls of the webs 32 and prevent the ring 36 from rotating in and relative to the piston itself.

In the modification of the invention, shown in Fig. '7, the new expander ring is generally indicated at 26 and is substantially similar to the ring 15 having upper and lower bearing edges 38 and 39, similar to the bearing edges 23 and 24. In this form of construction, however, the ring 26 has tool-receiving portions in the form of apertures 40 extended transversely therethrough, at points somewhat removed from the ends of the ring. This leaves end portions 41 which are similar to the end portions 27.

Without further elaboration the foregoing will so fully explain our invention that others may, by applying current knowledge, readily adapt the same for use under various conditions of service.

Having thus described our invention what we claim as new and desire to protect by Letters Patent is:

1. In a piston, the combination of a piston body having an expansible split skirt, a skirt expander ring arranged within the skirt, said ring having a. groove formed therein extending circumferentially therearound, and fastening elements mounted in the skirt having portions projected into said groove for securing the ring in position.

2. In a piston, the combination of a piston body having an expansible split skirt, a skirt expander ring arranged within the skirt, said ring having a circumferentially extending groove formed therein and having relatively sharp upper and lower edges bearing against and gouging slightly into the skirt under the pressure incident to the tension of the installed ring to prevent movement of the ring relative to and axially of said body, said ring having tool-receiving portions formed therein at points adjacent to but somewhat removed from its ends, and fastening elements mounted in the wall of the skirt having portions disposed in said groove for securing the ring in position.

3. In a piston, the combination of a piston body having an expansible split skirt, a skirt expander ring arranged within the skirt, said ring having a circumferentially extending groove formed therein and having relatively sharp upper and lower edges bearing against and gouging slightly into the skirt under the pressure incident to the tension of the installed ring, said ring having tool grip portions struck out therefrom providing apertures at points adjacent to but somewhat removed from its ends, and fastening elements mounted in the wall of the skirt having portions disposed in said groove for securing the ring in position, certain of said fastening element portions projecting into said apertures.

4. In a piston, a piston body including a split skirt having a row of apertures formed in the wall thereof, said apertures being spaced at intervals circumferentially around the wall of said skirt, an expander ring having a circumferentially extending groove formed therein, and fastening elements having portions mounted in said apertures and having other portions projected into said groove.

5. In a piston, a piston body including a split skirt having a row of apertures formed in the wall thereof, said apertures being spaced at intervals circumferentially around the wall of said skirt, a split expander ring having a circumferentially extending groove formed therein, and fastening elements having portions mounted in said apertures and having other portions projected into said groove, said ring having toolreceiving apertures formed therein at points adjacent to but somewhat removed from its ends.

6. Ina piston, a piston body including a split skirt having a row of apertures formed in the wall thereof, said apertures being spaced at intervals circumferentially around the wall of said skirt, a split expander ring having a circumferentially extending groove formed therein, said ring having tool grip portions struck out therefrom extending radially inwardly at points adjacent to but somewhat removed from its ends, andfastening elements including shanks mounted in said apertures and having heads projected into said groove.

7. In a piston, a piston body including a split skirt having a row of apertures formed in the wall thereof, said apertures being spaced at intervals circumferentially around the wall of said skirt, a split expander ring having a circumferentially extending groove formed therein, said ring having tool grip portions struck out therefrom forming slots in said ring at points adjacent to but somewhat removed from its ends, and

fastening elements including shanks mounted in said apertures and having heads projected into said groove, certain of said fastening elements having their said heads projected into said slots. 8. In a piston having an expansible skirt, an expander ring arranged within the skirt, said ring being recessed in the face contacting With the wall of the skirt, and fastening elements projecting inwardly from the skirt and having portions disposed within the recessed part of the ring for securing the latter in position.

LESLIE W. COOMBS. ARTHUR W. KUSHJNSKY. 

